Rotary keyboard punching machine



Mamzh` 8, 1960 o. ABBONDANZA ROTARY KEYBOARD PUNCHING MACHINE 8 Sheets-Sheet 1 Filed Sept. 17, 1957 lil Venta r.- OJl/al/do A bondnnza @f March 8, 1960 o. ABBoNDANzA 2,927,676

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ROTARY KEYBOARD PUNCHING MACHINE Filed Sept. 17, 1957 8 Sheets-Sheet 8 HuHEIbIFIEHH Akkrum] United States Pate'nt Oiee 2,927,676 Patented Mar. 8, 1960 2,927,676 ROTARY KEYBOARD PUNCHING MACHINE Osvaldo Abbondanza, Milan, Italy, assignor to Fabbrica Italiana Macchine Aziendali, Milan, Italy, an Italian company Application September 17, 1957, Serial No. 684,477 claims priority, application Italy october 24, 195e 9 claims. (c1. 1976.6)

There are known rotary punching machines capable of engraving data in metal plaques adapted for use as visible and indelible marks for a machine or a packaged material or as matrices for the printing of the data thus punched.

There are at least two categories of such rotary machines, of which in the lirst one the cooperating punches wanted are brought into punching position by means of a handwheel, whereupon the control for punching proper s actuated, while in the second category the control for the positioning of the punches is eected by means of a keyboard of the kind of a typewriter keyboard, the punching taking place automatically on completion of' the positioning operation.

In the types of keyboard punching machines known heretofore, the punch-carrying mechanism, represented generallyby two drums, on one of which the male punches are carried and on the other of which the female punches are carried, always turns in one direction until an abutment, controlled by the keyboard, meets a stopping arm turning together with the drums. The taking place of the meeting of the arm with the abutment automatically determines the punching.

In hand-controlled machines, controlled by means of,

a handwheel, the operator, knowing the progression of the letters, brings the wanted letter into punching position by turning the handwheel in one direction orin the other direction, of course selecting always the direction of rotation corresponding to the smaller angle.

It is themain object of the present invention to provide a rotary punching machine with keyboard control wherein the punch-carrying drums are turned automatically in the more convenient direction of rotation for every letter that is to be punched.

It is another object of the invention to provide the machine with such a braking system as to enable a soft meeting between the arm turning with the drums and the abutments controlled by the different keys.

In Fig. l there is shown diagrammatically a longitudinal section of the machine.

In Fig. 2 there is shown the system for determining the more convenient direction of rotation.

In Figures` 3a, and 3b there are shown two positions ofthe stoppingarm and of the associated controls, and in Fig. 3c there is shown a detail.

In Fig. 4 there is shown the electric circuit of the machine.

In Figures 5a, 5b and 5c there are shown three operating stages of the system of variable advance in the de-energizing of the rotating clutch and in the brake control. v v

In Fig. 6 there is shown a second possibilityvof con trol of the more convenient sense of rotation.

In Fig. 7 there is shown the control for capital letters.

In Fig. 8 there are shown the stages of the various operations which occur in every cycle of the machine.

The'machine (Fig. l) is constituted fundamentally by two punch-carrying drums 1 and 2 fitted onto the main shaft 3. At the periphery of the drums, within special seatings, there are accommodated the male punches 4 in the upper drum and the female punches 5 in the lower drum, or vice versa.

In the case illustrated it is assumed that the machine is equipped with pairs of punches corresponding to the letters of the alphabet, capital and small, to the series of numerals, capital and small, and to the dilferent punctuation marks and characteristic symbols.

The shaft 3 is controlled by a rotation reverser which may be built according to vany of the known principles.

In the case illustrated, a type with two bevel gears 6 and 7 (Fig. 2) has been selected, which are loose on the secondary shaft 8,`and which are always coupled with the bevel gear9, which is tted onto'the main shaft 3. The hubs of the gears 6 and 7 are coupled with the discs of the solenoid-operated clutches and 101 respectively.

With the gear 6 there is associated Ythe clutch 100 which controls the rotation in clockwise sense of the drums; and with the gear 7 there is associated the clutch 101 which controls the counterclockwise rotation of the drums. l

The control part of each clutch is tted onto the shaft 8 which is connected by means of a pulley 10 and belt to the shaft for controlling the punch-operating shaft 11, which in turn is connected by means of another pulley 12 and another belt to the motor 13 of the machine.

Onto the shaft of the drums there is tted a disc of material 14 whereon there are built up two conductive half-rings V102 and 103 and two` entire rings 104 and 105.

Upon that disc, iixed to the structure of the machine, there is a brush-carrying disc 15'wherein there are, in a rim of radius equal to that of the half-rings 102 and 103, as many brushes 106/1, 106/2 106/45 as there are keys in the machine (with the only limitation that this number should be odd for reasons which are set forth hereinafter-in the case of 90 pairs of punches there will be 45 keys and each key will serve to control a small letter punch and another punch for a capital letter).

in correspondence with the two whole rings, on the same disc 15, there are two further brushes 107 and 108 to which is connected the circuit for controlling the clockwise clutch 100 and counterclockwise clutch 101 respectively.

On thel shaft of the Idrums Ythere is tted the stopping arm 16, the middle line of which corresponds to the angular direction of the middle line of the insulating space 121 between the half-rings 102 and 103 indicated above.

Near the free end of the arm 16 there is provided a hole 17 within which there can move the end 18a .of the lever 13 fulcrumed on the stopping arm 16. The distration, by the energizing of a solenoid illustrated in Fig. i with numerals from 111/1 to 111/45. The energizing of the solenoid takes place by means of the closing of one of the contacts 110/1, 110/45' placed under each lever of said keys.

The stops 20/ 1, 20/45 are placed in an angular position which accurately corresponds to the brushes 106/1, 106/5. The two assemblies constitute thus two reference systems, one a mechanical one and the other one an electrical one. The lubbers line of the two systems is represented by the middle line of the recess 17 provided in the stopping arm 16 and by the middle line 121 between the two semi-rings 102 and 103, as indicated hereinbefore.

The two lubbers lines have the same angular position so that when the stopping arm 16 is in contact with the selected stop 20, the insulating space finds itself in correspondence with the corresponding brush 1,06.

From Fig. 4, which illustrates the electric Vcircuit of the machine, it will b e noted how under the'keyS, in addition to the series of contacts 1,10/1, 1.10/45, there is the other series 110/1', 110/45'. The closing of one of the contacts 110/1', 110/45' determines the energizing of one of the solenoids 111/1, 111/45, to which corresponds the lifting of one of the abutments 20/1, 20/45.

The closing of one of the contacts 110/ 1, 110/45 applies voltage to the brushes 106/1, 106/45, while the common conductor thereof is connected to the generator 112 through contact 115/ 1, actuated by a cam 115 connected with the punching shaft 11 (illustrated hereinafter), contact 116/1 closed at rest, actuated by the relay 116, and conductor 114.

The brushes 106/ 1, 106/ 45 are in contact with the half-ring 102 or 103. The half-rings are connected to the entire rings 104 and 105 which are connected by way of brushes 107 and 108 and conductors 117 and 118 to the relays 119 and 120 respectively.

The common conductor of these relays is connected, by way of the conductor 113, to the negative end of the generator. In that way, by pressing a key relative to any letter (see Fig. 2), for instance the one indicated with A, i

the contacts 110/1 and 110/1 are closed. The closingof the contact 110/1' determines, as seen, the lifting of the stop 20/ 1. The closing of the contact 110/1 applies Voltage-owing `to the contacts 11S/1 and 116/1 being closed-to the brush 106/1 from which the voltage is transmitted to the half-ring 103 and, therefore, to the associated ring 104 and, through ductor 118, to the relay 120 which thus becomes energized. To said energizing there corresponds the closing of the contact 120/1 and, therefore, the energizing of the coil of the solenoid operated clutch 100. The shaft of the drumsl will then turn in a clockwise direction as long as the relay 120 remains energized. If voltage were supplied to said relay without passing over the contact 116/1, the clutch 100 would become energized until the rotation of the half-ring 103 fixed to the disc 14 fitted onto the drum shaft, brings the insulating section 121 between the two halfrings under the brush 106/ 1, that is, after covering the angle a (Fig. 3). At that time the pair of punches male and female, relative to the letter A, would have arrived at punching position, after the clock-wise rotation which in the case of the scheme, is the one to which the smallest angle corresponds, namely the very angle a mentioned above. The evidence of the choice of the shortest way for bringing the punch A to punching position, results from the perspective View of Fig. 2. As already seen, the stops 20/1, 20/2, 20/45 and the brushes 106/1, 106/45 are arranged respectively in the same angular position and in fixed position, while .on the rotary part there are connected the respective lubbers lines 16 and 121 together with the punches arranged in radial alignment with their respective stops and brushes.

the brush 108 and conln that way the angle a by which the lubbers line 16 will have to rotate to come into contact with the stop, will be the same angle by which the punch A is distant from the punching position. Hence the punching takes place when the arm is in contact with the stop and the middle line of the insulating space 121 is below the brush 106/1 and the punch A is under the punching hammers 21.

From what has been set forth hereinbefore it will appear clearly how the number of the keys and brushes 106 must be an odd number. In fact, at the end of every search, the brush of the controlled key comes to ind itself in the insulating interspace 121, so that of the other brushes one-half will be in contact with the half-ring 102 and the other half with the half-ring 103, while none will be in contact with the other insulating interspace 121/1. This condition is satisfied by an odd number of brushes: in the illustrated case, the brushes are forty-five. of which one is in contact with the insulating space 121, while twenty two are in contact with the half-ring 102 and other twenty two are in contact with the half-ring 103. The dimensions of the insulating space 121 in the case illustrated will have to be subtended by an angle smaller than 1/{15 of 360.

From that arrangement it will now appear clearly how the unit is always in a position to take any punch to punching position according to an angle of rotation smaller than 180 and how that angle will always be the smaller one that exists between any punch and the punching position.

The punching hammers 2'1 are carried by two jaws 22 and 23`fulcrunied on the shoulders 24 and 2 5 of the machine and controlled by means of various lever systems known per se, by an eccentric 11a controlled by the punching shaft 11.

To explain the search of direction, it has been assumed here that the clutch is energized until the arrival of the brush 106 in correspondence with the insulating space 121. This would not be convenient in practice, since under that condition, the unit, having a rather considerable kinetic energy, would strike violently against the abutment by means of the rotary arm. Reduction of that energy is provided, according to one first embodiment, by an advancing and braking system illustrated in Fig. 3.

Displaced with respect to the reference line by a cer tain angle X (to be determined in relationship with thc moment of inertia of the system, withthe time of energizing of the selected brake, -with ,the braking couple thereof and with other considerations), there are the two small levers 26 and 27 which by means of an elastic connection with the levers `28 and A20 come into contact with the plunger of one or the other of two quick breakers 122 and '123 whose contacts 122/1 and `123/1 are normally open.

lf, again according to the preceding example, the drum has to perform a clockwise rotation of a degrees, to take the punch A to the punching position, before the stopping arm cornes into contact with Athe abutment 2.0/1, the small lever 27 advances the arrival at said abutment by an angle X thus closing the contact 122/1 which in tum energizes the relay 116. The energizing of said relay has the following consequences:

(a) 'Ihe contact 116/1 of the relay 116 is opened whereby voltage is taken from the common one of the contacts 11G/1, `1110/45 land, therefore, from the direction relay 119 (or 120'). The dce-energizing of the relays 119 and 120 has the effect .of disconnecting 4the clutch 100 or 101 from the drive shaft `8.

(b) The contact 116/2 is closed, whereby from the contact /1 normally closed .there arrives voltage tothe coil of the electromagnetic brake 124, whose rotary part is fitted onto the axis'of the drum 1. Said brake may even be of another kind, provided it can be controlled by a solenoid. `'In that way the rotary masses associated with the punch-carrying .drums are Vdisconnected lfrom the drive and braking shaft prior to the occurrence of .the

impact between the abutment and the stopping arm. When said impact takes place, the small arm 18 closes the contact 109/1 or 109/2 according to the direction of rotation, thereby energizing the relay 125 and the clutch 126 for initiating the punching. A v

From the positive pole of the generator, by way of normally closed contact 127/1 and contactv 125/ 1, closed when the relay is energized, there is'kept the voltage for` the punching clutch 126. The rotation of the punching shaft 11, if put in rotation by the clutch 126, in additionV mentpreviously energized with consequent lowering of theabutment and opening of the contacts 109/1 or 109/2 (therelay 125 being however self-energized, remains in active position).

De-energizing of the brake solenoid 124. Thispermits `the small positioning tooth 31 to rotates the cams 115 and 127 cited l correct the v position of,

the drum which isno longer braked, so as to have an Yaccurate position of the punching of the letter. All the circuits thus return to their rest conditions, except the punching circuit. f

In the same stage in which the contact 11S/1 opens, the keyboard is released, by way' of lever systems 32, 33, 34, so permitting the operator todepress the subsequent key desired, evenbefore termination ofthe punching.

A disc 35 is lifted thus acting upon the ends 36 of the small levers 37 actuated by the solenoids 111, so as to ensure the 'lowering of the abutments 20 the solenoids 111v of which are already de-energized, as said above.

Towards the end of punching the cam 127 opens'the contact 127/1 thereby de-energizing the relay 125 and the clutchy 126.

The inertia of the masses `associated with the-shaft 1l (which is rather small) is annulled by the considerable passive resistance and by a small mechanical brake not shown in the drawings.

Yln Figures 3a and 3b there are visible the positions of the smallarm 18, of the contacts 109, of the breakers 122 and 123 andof the abutment 20 at rest and in action. In Fig. 3a all-,the members are at rest prior to the occurrence of the rotation through the angle a, to take the punch A to the punching position. The contacts 109/1 and 109/2 are open and the breakers 122 and 123 are not actuated. Within the recess 17 there is visible the abutment 20 with which the stopping arm had come into contact in the previous search. In Fig. 3b, after a clockwise rotation by the angle a, the `small arm 18 has performed the stroke admissible for it within the recess 17 following the impact against the abutment 20 relative to the letter A; the contact 109/1 is closed and the breaker 123 has been actuated when, with the advance of X degrecs, the small lever 26 has come into contact with the abutment 20.

In that position the lubbers line l of the arm 16 is in contact with the desired abutment.

The braking system just described brakes in a safe and l accurate manner, assuming the slipping of the clutches to'be negligible, that is, assuming that, for the different values of the angles of rotation, there are no obnoxious variations of angular speed. In order to'take into account, instead, the possibility of such variations of angular speed kforvsm'all angles, it is possible to use another system for controlling the braking relay114placed in parallel tothe one indicated above. This second system is )illustrated in Fig. 5.

Onto the' main shaft 3 there 38 whereon, in rest position and inthe rotational stage, there engage the teeth of a rack 39 which during rotation slides longitudinally within aguide 40." At the end' of the rack there is connected a small lever 41 fulcrumed at 42; to that leverthere is connected another small lever 43 fulcrumed in the disc 14 which carries the half-rings 102 and 103. Following a rotation, for instance a counterclockwise one, of the main shaft 3, by an angle B, the rack 39 is displaced towards the right of Fig. 5b and, consequently, the space 121 betweenthe half-rings 102 and 103 is rotated in 'clockwise sense, by an angle fy. In that way the middle line will vr.arrive'atL correspondence with' the brush 10o-'urged in advance by-said angle 7, with respect to the` arrival'of the stopping arm 16 at the abutment 20. Said advance is proportional to the angle of rotation by'which the drums should turn (it increases'with said angle), so as to introduce a variable advance to the deener'gizing of the clutches for rotation control, as well as to the energizing of thebrake.

If said angle 'y (Fig. '5) is greater than the angle X (Fig. 3) of fixed advance of the small levers 26 and 27, it will be `the arrival of the brush 106 on the insulating section 121 which breaks' the circuit of the relays for direction,`119 or v120 (Fig, :2).

If the shaft 3 wllfhave been stopped and there will have begun (as illustratedhereinbefore) the stage of punching, va control (not shown in thedrawings) connected to the compressing jaws 22 and 23 will push ythe Vguide 40 in'Ithe direction indicated by the arrows 44 and 45 (Fig. 5e) so'as 'to disengage the rack 39 from the pinion 38. In that position the small lever 41, pushed by the small levers 46 and 47 connected to leach' other by the spring 48, will make the rack 39 slide within the, guide 40 to take it back to centered position with respect to the pinion By effect of vthe same actionQthe too will return to normal or rest position.'-

When on termination of compression the punching jaws 22 and 23 will lift again `the small hammers 21 and 22,*the guide 40 will be taken again towards they axis and the rack 39 will engage'again the pinion 38 as shown in Fig. 5a. 1 Y j n The system of selection of the minimum; angle ot"V rotation as described above, and which -is of electro` mechanical-character, may be arrived at in another manner, lwith prevailingly mechanicalA byFig.6. ,e

In Eig. 6, v'on the Vshaft 3 there are iitted two half-discs 49 and 50, each of Vwhich extends through an angle of and which are staggered axially and angularly. i e The keys 50/1, Sil/,'45, if actuated, lift the abutments20/ 1, .f 20/45 and at the same time, bymeans of tie rodsSl/l, 51/45, angle levers 52/1, 52/45 and tie rods 53/1, 53/45, they actuate the shears S4/1, 54/45. To the carrying structure of the machine there are connected the contacts 55/1, 55/1, .g., 55/45, 55/45; whose" upper contacts 55/1, 55/45 close the control circuit for clockwise clutch 1,00, while the lower contacts 55/1, 55/45 close thecontrol circuit for counterclockwise clutch 101. It is thus clear how also in this case according to the position of the shaft' 3` and, therefore, of the semi-discs 49 and 50, by depressing a certain keyone determines the closing of one of the upper contacts or of oneof the lower contacts, the closing of the other of the two .contacts being hindered by the presence of one offthe two half-discs. Also this system so solves the problem of search for the more convenient direction of rotation.

As will be noted, there is a complete analogy between this second method and the first one. For the system of the semi-rings there have been substituted two semidiscs; for',` the series4V of brushes there have been substituted twoseries of contacts.

It should be understood that'the solution of the probi is tted a toothed 'pinionf Y methods,` as illustrated l lem can be arrived at by utilizing part ofthe `iirst system and part of the second system. For instance, it is possible to replace the solenoids for controlling the abutments, with mechanical controls and rods controlled mechanically by the keys and constituted in a manner analogous to typewriters.

The system indicated utilizes a number of keys `which is half the number of punches contained in the punchcarrying drums 1 and 2, in analogy to what is done in typewriters. To utilize each key for the control of two punches there is needed, therefore, a system for interchanging small and capital letters.

The system adopted is illustrated diagrammatically in Fig. 7. By means of of levers 56, 57, 58, there is determined .the rotation of the punch-carrying support 19 by an angle equal to that provided between each small letter punch and its adjacent capital letter punch (a and Ain the case of Fig. 7), so as to take the punch and solenoid from the `position indicated by solid lines to that indicated by dotted lines. At the same time, also theinsulating disc 1S, which contains all the brushes, is rotated by an equal angle so as to take the brush involved to the position indicated by dotted lines, that is, into contact with a half-ring.

If now it is assumed that the letter a was punched an action upon the key M by means previously and that the capital letter key was depressed,

of the punch-carrying disc 19 and of the brush-carrying disc 15, if the key corresponding to the letter A is pushed by way of the brush 106 and half-ring 103, the clockwise rotation circuit for the clutch 100 will be closed and the shaft 3 will rotate in such a way as to take again the stopping arm into contact with the abutment.

Following that rotation, punching position.

Another feature of the unit appears in the case of the repetition of the punching of a letter.

As illustrated he'reinbefore, if a punch has already been actuated, the brush corresponding to the letter finds following the rotation now the punch A will be in itself in the insulating space between the two half-rings and the stopping arm finds itself with its reference in correspondence with the abutment actuated.

On pressing again the key corresponding to the same punch (case of double letters), the brush, nding itself in the insulating space, cannot determine the actuation of the clutch and, therefore, the shaft remains fixed. The abutment involved, however, is actuated nevertheless, and in lifting, it displaces the small arm 18 so asto 'close the contact 109/1 or `109/2 thus determining, as we have seen, the punching action (Fig. 3c).

In orderithat the abutment may be able to rise, said abutment has wedge-shape, and so has the lower portion 18a of the small arm 18. Hence if the abutment 20 is actuated by the solenoid 111, the small arm 18 is displaced, as said above, in such wayY as to close the contact for punching control.

For a complete survey of the operating stages, the diagrams of Fig. 8 are referred to.

The stage I relates to the period of rotation. The rotation begins at the time A (when the clutch is energized) and ends at the time C (when the stopping arm comes into contact with the abutment).

The stage II relates to the period of closing of the contact 122/1 or 123/1. The time B of the beginning of closure is the time of the arrival of the small arm 26 or 27 at the abutment 20. The difference between the times C and B represents the advance in time due to the angle X by which the small levers 26 and 27 are displaced from the line of reference.

The stage III comprises the perodin which punching takes place. The starting time C'corresponds to .the end of rotation (closing of the contacts 109/1, 109/2).

The stage IV relates to the closing of the contacts 109/1 or 109/ 2 and is the cause of the beginning of the stage III. Times Cfand D. Y

The stage V relates to the duration of the energizing of the relay 119 or 120 and of the clutch 100 or 101. The time B in which said 'stage ends, corresponds to the beginning of the stage AIl. (closing 122/1 or 123/1 by which said time is determined).

The stage VI relates to the duration of the braking and is confined by the times B and D (closing 122/1 or 123/1 and opening 11S/1 as stage VII).

The stage VII above the base line reports the time in which the contact 11S/1 has opened since said stage begins at the time D. It will be noted that at the end of the cycle the contact is still closed: this is a condition indispensablefor the beginning of the subsequent cycle.

The stage VIII, which begins at the time E, expresses the stage in which the keyboard is released. At the end of said interval of time it is already possible to depress the subsequent key, that is, even prior to the ending of the cycle in course. -This circumstance serves to accel erate the rhythm of typing.

The stage IX relates to the opening of the contact 127/1 at the time F. The period is very short and serves only to take the self-energizing away from relay 125. At the end of the cycle of punching, this contact is closed again. From the time F till the time G there takes place the termination of punching with de-energized clutch. The movement `of the shaft is due only to the forces of inertia.

' Having so illustrated the principles of embodiment of a keyboard punching machine with instantaneous determination of the more convenient direction of rotation, We wish to point out that this principle may be utilized in various other applications and, to remain in the field of business machines, for instance in rotary card holders with calling of the card by means of keys. In `such apparatus, the rotating panels are marked with a numeral and the desired panel is called by pressing one or more keys.

To get the search in the more convenient direction it suiiices to thinkof connecting to the shaft for rotation of the panels, directly or by means of a transmission, an insulating disc with half-rings according to what has beenrset forth hereinbefore. To the individual keys (or in combination as in the case of the capital and vsmall letters or according to more than two combinations), there will be connected a brush, while the series circuit, including the key, brush, and half-ring will end at one or the other clutch coil (or at one or the other remote control switch of a remote control reverser in the case in which the reversal of direction is more economically obtainable by `means of the reversal of one phase of au alternating current motor), thus determining the Vrotation according to the smaller angle.

1. A machine for printing characters on metal plates, comprising a disc having a plurality of punches peripherally arranged thereon, said disc being mounted to rotate to bring said punches selectively into punching position, a rst arcuately formed sector, a second arcuately formed sector, each of said sectors having an extent of less than and mounted to rotate with said disc, an angularly xed selection member for each character mounted to be movable into and out of operative position, a keyboard having a key for each of said members, said keys being connected to the respective members to move a member into operative position upon depression ofthe associated key, said rst sector being disposed to interfere with a group of said members, when any one of said group is moved to operative position, said second sector being disposed to interfere with another group of said members when any one of said second group is moved to operative position, a first circuit means for vrotating said disc in one direction in response to the interference of a member of said rst group with said first sector and a second circuit means for rotating said disc in the other direction in response to the interference of a member of said second group with said second sector to bring one of said punches into operative position, Iand means t0 actuate each of said punches whenfit is in punching position.

2. A machine according to claim 1 comprising a stopping member, and an arm mounted to rotate with said disc, each of said circuit means selectively actuating said stopping member to strike against said arm.

3. A machine according to claim 2 wherein said arm is provided with an intermediate member mounted to be resiliently displaceable upon striking said stopping member, and wherein the actuating means for the punches includes a first switch and a second switch which are selectively operated by said intermediate member depending upon the direction of rotation of said disc.

4. A machine for imprinting characters on metal plates, comprising a disc having a plurality of punches peripherally arranged thereon, said disc being mounted to rotate to bring said punches selectively into a punching position, a first arcuately formed sector, a second arcuately formed sector, each of said sectors having an extent of less than 180, an angularly fixed selection member for each character mounted to be movable into and out of operative position, a keyboard having a key for each of said selection members, said keys being connected to the respective members to move a member into operative position upon depression of the associated key, said first sector being disposed to interfere with a first group of said members when any one of said group is moved to operative position, said second sector being disposed to interfere with a second group of ,said members when any one of said second group is moved to operative position, said disc having an arm rotatable therewith, a stopping member, a first circuit means for rotating said disc `in one direction in response to the interference of a selection member of the first group with said first sector, a second circuit means for rotating said disc in the other direction in response to the interference of a selection member of the second group with said second sector, each of said circuit means actuating said stopping member, and a switch means attached to said disc and disposed in advance of said arm in each direction of rotation, said switch means opening each of said circuit means in response to its interference with a said stopping member a predetermined distancev in advance of the striking of said arm against said stopping member, thereby deenergizing the rotational means for said disc.

5. A machine according to claim 4 comprising means to actuate each of said punches when it is in punching position, and an intermediate element which initiates operation of said actuating means in response to the lifting of the stopping member when said arm is already in correspondence with said stopping member.

6. A machine for imprinting characters on metal plates, comprising a disc, said disc having a plurality of punches peripherally arranged thereon, each of said punches corresponding to a selected character to be printed, a second group of punches each being arranged peripherally on said disc and spaced a predetermined angle from each of the first-mentioned punches, said disc being mounted to rotate to bring a selected one of said first group of punches to punching position, a manual lever means, means connecting said manual lever means for rotating said disc to bring a selected one of said second group of punches to punching position upon actuation thereof, a first arcuately formed sector, a second arcuately formed sector, each of said sectors having an extent of less than 180, an angularly fixed selection member foreach character, a keyboard having a key for each of said members, said keys being connected to the respective members to move a member into operative position before depression of the associated key, said first sector being disposed to control one group of said members when any one of said group is moved to operative position, said second sector being disposed to control a second group of said members when any one of said second group is moved to operative position, a first circuit means for rotating said disc in one the interference of a membercomprising a disc having a plurality of punches peripherally arranged thereon, said disc being mounted to rotate to bring a selected one of said punches to punching position, a second disc mounted to rotate with said first disc, a first arcuately formed conductor mounted on said second disc, a second arcuately formed conductor mounted on said second disc, each of said conductors having an extent of less than an angularly fixed contact brush for each character to be printed, each of said brushes adapted to slide against said first and second conductors during rotation, a group of brushes being in contact with said first conductor and a group of said brushes being in contact with said second conductor, a keyboard having a key for each brush, said keys electri-Y cally connecting a brush upon depression of the associated key, said first conductor being electrically connected with a first annular ring of conductive material mounted to rotate with said disc, said second conductor being electrically connected with a second annular ring of conductive material mounted to rotate with said disc, a first circuit means including said first annular ring and said first arcuately formed conductor for rotating said disc in one direction in response to the operation of a selected key, and a second circuit means including said second annular ring and said second arcuately formed conductor for rotating said disc in the other direction in response to the operation of a key.

8. A machine for imprinting characters on metal plates, comprising a disc having a plurality of punches peripherally arranged thereon, said disc being mounted to rotate to align a selected one of said punches to punching position, a first semi-circular member, mounted to rotate with said disc, a second semi-circular member diametrically opposed to said first member and mounted to rotate with said disc, a plurality of peripherally disposed devices mounted to selectively correspond with said first and second semi-circular members, one of said devices being for each character to be imprinted, a keyboard having a key for each of said devices to selectively actuate its corresponding device upon the operation of its key, and circuit means including each of said devices for rotating said disc in both directions, said circuit means being effective to rotate said disc in one direction when said first semi-circular member is in correspondence with a selected device, said circuit means being effective to rotate the disc -in the other direction when said second member is in correspondence with a selected device.

9. A machine for improving characters on metal plates, comprising a disc having a plurality of punches peripherally arranged thereon, said disc being mounted to rotate to align a selected one of said punches to punching position, a first arcuately formed sector, a second arcuately formed sector, each of said sectors having an extent of less than 180, an angularly fixed selection member for each character mounted to be movable into and out of operative position, a keyboard having a key for each member, said keys being so connected to move a member into operative position upon the depression of the associated key, said first sector being disposed to control a group of said members when any one of said group is moved to operative position, said second sector being disposed to control a second group of said members when any one of said second group is moved to operative position, a first circuit means for rotating said disc in one direction through a predetermined angle in response to the interference of a selection member with a second circuit means for rotating said disc through a predetermined angle in the other direction in response to the interference of a selection member with said second sector, an annular member mounted to rotate with said disc, and lever means connecting said rst and second sector to said member, said lever means varying the angular position of Said rst and second `set:- tor relative to said disc depending on the distance said disc is caused to rotate.

ReferencvesCited in `the file of this patent UNITED `STATES PATENTS 

